A conventional apparatus which manipulates a minute object has an arrangement shown in FIG. 14 (Japanese Patent Laid-Open No. 5-323203). The apparatus shown in FIG. 14 has a micromanipulator 103 installed in an inverted microscope. The micromanipulator 103 is arranged near a stage 106 provided in the inverted microscope. The distal end of a perforator 104 as a tool is placed in a petri dish 105 mounted on the stage 106.
An objective lens 101 attached to a revolver 102 is arranged under the stage 106. The magnification is changed by rotating the revolver 102 to switch the lens to the objective lens 101 with another magnification power. Observation light which has passed through the objective lens 101 is converted into an electrical signal by a TV camera 108, sent to a monitor device 109, and displayed on it. Simultaneously, direct observation through an eyepiece 107 is also possible.
The apparatus also has a joystick 113 to be operated by an operator as the operation unit of the micromanipulator 103. The tilt direction and tilt angle of the joystick 113 are detected by an angle detector 112 and input to a CPU (control circuit) 111 as an electrical signal. The CPU 111 operates a power amplifier 110 in accordance with the signal from the angle detector 112 to drive the manipulator 103.
As a microscope, a microscope with a zoom lens is also known. When such a device is used, the magnification of an object can continuously be changed. Hence, as compared to the system which switches the objective lens 101 by the revolver 102 shown in FIG. 14, the work can smoothly be executed.
The prior art has the following problems because the observation system does not synchronize with the tools.
More specifically, when the work is done while switching the observation magnification, and the operator moves a tool (e.g., a perforator) by using a command value input means such as a joystick, the tool moving amount observed on the monitor changes even when the input value does not change.
In this case, the operator must perceive the observation magnification and adjust the input command, resulting in very cumbersome work. Especially, when the magnification power is increased, and the same command value as that for a low magnification power is input, the tool moves largely. This makes it difficult to perform fine manipulation.
Normally, the observable working space is small when the magnification power is high. For this reason, the tool or manipulation target object may move out of the visual field in the worst case. Conversely, when the gain is adjusted for minute manipulation, a problem is posed when the operator wants to largely move the tool under a low magnification.